Lubricant injector

ABSTRACT

A lubricant injector includes a lubricant inlet, a lubricant outlet, a control piston and a metering piston. The control piston is configured to conduct lubricant from the lubricant inlet to the metering piston, and the metering piston is configured to pump the lubricant provided by the control piston to the at least one lubricant outlet. The metering piston includes a first metering chamber and a second metering chamber that are each connected to the at least one lubricant outlet. The lubricant injector further includes first and second lubricant channels, and in a first switching state of the control piston the lubricant inlet is connected via the first control space to the first lubricant channel and the second metering chamber, and in a second switching state the lubricant inlet is connected via the second control space to the second lubricant channel and the first metering chamber.

CROSS-REFERENCE

This application is the U.S. National Stage of International ApplicationNo. PCT/EP2015/055921 filed on Mar. 20, 2015, which claims priority toGerman patent application no. 10 2014 205 975.5 filed on Mar. 31, 2014.

TECHNOLOGICAL FIELD

The present invention relates to a lubricant injector for delivery oflubricant to at least one lubricant outlet point as well as a lubricantinjector block with at least two such lubricant injectors.

BACKGROUND

Lubricant injectors, also called lubricant distributors, are known inthe prior art and are often used as part of centralized lubricationdevices with which a lubricant is dispensed from a central lubricantsource to at least one lubricant consumer. Here the lubricant injectorusually includes a lubricant inlet that is connected to a lubricantsource, in particular a lubricant pump, wherein the lubricant sourcesequentially pumps pressurized lubricant to the lubricant injector.Furthermore, the lubricant injector usually includes a control pistonthat is designed to guide lubricant from the lubricant inlet into ametering chamber of a metering piston, out from which the quantity oflubricant available in the metering chamber is delivered to thelubricant outlet and then to the lubricant consumer.

Lubricant injectors are known from the prior art, for example, EP 1 631767 (family member of US 2005/258004), DE 602 15 036 (family member ofU.S. Pat. No. 6,986,407), or EP 1 779 023 (family member of US2008/289906), whose control piston is displaceable under the lubricantpressure present at the lubricant inlet against the effect of a firstreturn spring into a metering position wherein the control pistonreleases a passage of lubricant to a first metering chamber. Themetering piston itself is also displaceable against the effect of asecond return spring, whereby the lubricant present in a second meteringchamber is urged toward a lubricant outlet chamber and from there to alubricant outlet. In the event of lubricant discharge at the lubricantinlet, for example, due to the lubricant pump cycle, the metering pistoncan be transferred into its initial position, whereby the lubricantpresent in the first metering chamber is transferred into the secondmetering chamber and a dispensing chamber.

However, it is disadvantageous with the lubricant injectors known fromthe prior art that they must be assembled from very many components, andare already very complicated to manufacture due to the two requiredreturn springs and the required connecting channel between the differentchambers. Moreover, the metering chamber and the metering piston must bemanufactured sufficiently large such that sufficient lubricant can beprovided per lubricant pump cycle to the lubricant outlet. The lubricantinjector thereby occupies a large installation space.

Alternatively it has been proposed in the prior art, for example, DE2433811 or also DE 10 2006 012 810 (family member of us 2006/213725), todispose the metering piston and control piston adjacent to each other inorder to reduce the installation space requirement of the injector.However, in order to supply such lubricant injectors with lubricant, atleast two lubricant-supply points must usually be provided for the twoswitching states of the control piston. This in turn necessitates alarge installation-space requirement outside the lubricant injector,and/or further elements, such as, for example, valves or distributors,that ensure that lubricant can be provided to the two lubricant-supplypoints.

SUMMARY

The object of the present invention is therefore to provide a robust andreliably functioning lubricant injector that requires little space andis simple to manufacture here.

The inventive lubricant injector includes a housing with at least onelubricant inlet and at least one lubricant outlet, as well as a controlpiston and a metering piston, wherein the control piston is designed toguide lubricant from the lubricant inlet to the metering piston. Themetering piston is furthermore designed to pump lubricant provided fromthe control piston to the at least one lubricant outlet. Here theinvention is based on the idea to form the metering piston such that themetering piston includes a first metering chamber configured as a firstpiston workspace and a second metering chamber configured as a secondpiston workspace, which are each directly connected to the at least onelubricant outlet. Due to the lubricant injector thus formed, lubricantcan both be guided both directly from the first metering chamber andfrom the second metering chamber, preferably without pressure loss,directly to the at least one lubricant outlet without the lubricant, asknown in particular from DE 602 15 036, first having to be guided fromone of the metering chambers into an outlet chamber.

Furthermore the lubricant injector further includes a first lubricantchannel and a second lubricant channel, wherein the first lubricantchannel connects the first metering chamber to the lubricant inlet orthe lubricant outlet, and the second lubricant channel connects thesecond metering chamber to the lubricant inlet or the lubricant outlet.Since the first and the second lubricant channel can be used both aslubricant supply to the metering chambers and lubricant removal from themetering chambers, the channels provided in the housing of the lubricantinjector are significantly reduced, which simplifies manufacturing.

In order to provide a robust- and space-saving-as-possible lubricantinjector, the control piston furthermore includes a first control space,in particular a first ring space, and a second control space, inparticular a second ring space, and thus defines a first switching statewherein the lubricant inlet is connected via the first control space ofthe control piston to the first lubricant channel and the secondmetering chamber of the metering piston. In contrast, in the secondswitching state the lubricant inlet is connected via the second controlspace of the control piston to the second lubricant channel, rather thanthe first metering chamber of the metering piston.

Even with adjacently disposed control piston and metering piston onlyone lubricant inlet may be available, which supplies either the firstcontrol space or the second control space with lubricant. This in turnsignificantly simplifies the construction of the lubricant injector,since the in any case available control piston also controls whether themetering chamber is connectable to the lubricant inlet or the lubricantoutlet. Furthermore, with the proposed lubricant injector more lubricantcan advantageously be provided from the lubricant injector to thelubricant outlet without enlarging the installation space. In additionthe construction of the lubricant injector can be significantlysimplified since no connection need be produced between the first andthe second metering chamber or a further return element be provided forthe metering piston. An expensive adapting of the return elements to oneanother can thereby be eliminated. In addition, a relatively largemetering bandwidth can be provided with the inventive lubricantinjector.

According to one advantageous exemplary embodiment the first lubricantchannel is connected via a first lubricant outlet channel, and thesecond lubricant channel via a second lubricant outlet channel, to theat least one lubricant outlet. The advantageous lubricant outletchannels here ensure a simple guiding of the lubricant from therespective lubricant channel or the respective metering chamber to theat least one lubricant outlet. In addition, in the other correspondingswitching state this lubricant outlet channel can be closed off in asimple manner using the control piston.

As mentioned above, in one advantageous exemplary embodiment in a firstswitching state of the control piston the lubricant inlet is connectedvia the first control space of the control piston and the firstlubricant channel to the second metering chamber of the control piston,while in the second switching state the lubricant inlet is connected viathe second control space of the control piston and the second lubricantchannel to the first metering chamber of the control piston. On theother side here in the first switching state of the control piston thefirst metering chamber of the metering piston is connected via thesecond lubricant channel and the second control space of the controlpiston to the at least one lubricant outlet, while in the secondswitching state the second metering chamber of the metering piston isconnected via the first lubricant channel and the first control space ofthe control piston to the at least one lubricant outlet.

Via the correspondingly disposed control spaces the control piston canbe controlled using the lubricant introduced via the lubricant inlet andtransferred from a first switching state into a second switching state.Depending on the respective switching state lubricant is in turn pumpedfrom the first or the second metering chamber to the lubricant outlet,while the respective other metering chamber is simultaneously impingedwith lubricant. During a pumping cycle a lubricant pump connected to thelubricant inlet can thereby provide lubricant both from the first andfrom the second metering chamber to the lubricant outlet, whereby theprovided lubricant amount increases overall.

However, such a design of the inventive lubricant injector also has thefurther advantage that the lubricant need not be provided from the firstor the second metering chamber to the same lubricant outlet, rather, asa further preferred exemplary embodiment shows, it is possible toprovide a first and a second lubricant outlet that are each impingedwith lubricant with the lubricant from the first or second meteringchamber. Using one lubricant injector lubricant can thereby not only, asin the prior art, be provided to one lubricant outlet, rather it ispossible to simultaneously supply two consumers with lubricant.

Here it is particularly advantageous if the first lubricant outlet isconnected to the first lubricant outlet channel and the second lubricantoutlet to the second lubricant outlet channel.

According to a further advantageous exemplary embodiment alubricant-outlet connecting channel is provided that connects the firstlubricant outlet and the second lubricant outlet. If, for example,lubricant is to be provided to the first consumer only every two orthree pumping cycles, which is realizable, for example, via a valvedisposed at the lubricant outlet, then the excess lubricant can bepumped from the respective metering chamber also to the respective otherlubricant outlet via the lubricant-outlet connecting channel. It isadvantageous here in particular if one of the lubricant outlets isconfigured closable. If, for example, in a field of use it is onlynecessary to impinge a single consumer with lubricant via the lubricantinjector, then the second lubricant outlet can be closed using a closureelement. A differently-structurally-designed lubricant injector is notnecessary for this. The stock keeping for lubricant injectors is therebyreduced since a single lubricant injector can be used for a variety offields of use.

In order to further increase this varying usability of the lubricantinjector, it is preferred, as a further advantageous exemplaryembodiment shows, to provide on the at least one lubricant outlet apreferably interference-fit, releasable connecting device, in particulara screw thread, a snap connection, and/or a plug connection that isdesigned to connect the lubricant outlet at least to an outlet closureelement or a lubricant-line connection element for connecting alubricant line or a valve unit. The inventive lubricant injector canthereby be used in a simple manner in the desired type of application.The at least one lubricant-outlet connecting channel disposed betweenthe lubricant outlets ensures here that an odd number of lubricantoutlets can also be provided using the inventive lubricant injector.

In addition to the first and/or second lubricant outlet, another furtherlubricant outlet can also be provided at the first and/or secondlubricant outlet channel.

According to a further advantageous exemplary embodiment the lubricantinjector furthermore includes a control-piston preload element, inparticular a return spring, that preloads the control piston in one ofthe switching states, preferably the first switching state. Here thepreload of the control-piston preload element can be adjustable. Herethe control-piston preload element makes it possible that if a lubricantpressure abutting on the lubricant inlet drops below a certain thresholdvalue the control piston is returnable into the first switching state.The size of the lubricant-pressure threshold value here can bedetermined via the preload force of the preload element. A decrease ofthe lubricant pressure usually occurs at the end of a pumping cycle ifno further lubricant is conducted from the lubricant pump into thelubricant supply line and to the lubricant inlet.

In addition, at least one of the lubricant outlets can advantageously beconfigured as a spring space for the control-piston preload element. Aparticularly compact lubricant injector can thereby be provided. Inaddition, such an arrangement of one of the lubricant outlets makes itpossible that a lubricant pressure abutting on the lubricant outletconfigured in this manner supports the return element and thus areturning of the control piston into the first switching state. This canbe advantageous in particular with low ambient temperatures.

On the other hand, in order to transfer the control piston from thefirst switching state into a second switching state, the control pistonis furthermore advantageously equipped with a control-piston workspacethat is impingeable with lubricant in order to transfer the controlpiston into the second switching state against the preload of thepreload element. Here it is advantageous in particular if thecontrol-piston workspace is connected to a lubricant switchover pressurechannel that is designed to conduct lubricant into the control-pistonworkspace if a certain lubricant pressure is reached or exceeded at thelubricant inlet and/or in the first control space of the control piston.Using this pressure-determined controlling of the control piston,complex control devices can be omitted, which in turn simplifiesconstruction and reduces costs.

A further aspect of the present invention relates to a lubricantinjector block that includes at least two of the above-describedlubricant injectors. Here the lubricant injector block can preferablyinclude at least one central lubricant inlet and a central lubricantoutlet, wherein the central lubricant outlet is configured to connectthe lubricant injector block in series to a further lubricant injectoror a further lubricant injector block. Furthermore a central lubricantchannel can be provided on the lubricant block that supplies thelubricant inlets of the lubricant injectors disposed in the block withlubricant. A plurality of lubricant consumers can thereby advantageouslybe supplied with lubricant. Since in particular the first meteringchamber and the second metering chamber are connectable to independentlubricant outlets, with an inventive lubricant injector exactly twoconsumers can be supplied with lubricant. However, this also means thatwith an injector block with which, for example, eight consumers are tobe supplied with lubricant, according to the invention due to the atleast two lubricant outlets only four lubricant injectors need to beprovided in the lubricant injector block. Thus the installation spacecan be reduced and costs reduced.

Further advantages and advantageous embodiments are defined in theclaims, the description, and the drawings.

In the following the invention shall be described in more detail withreference to the exemplary embodiments depicted in the drawings. Herethe exemplary embodiments are of a purely exemplary nature and are notintended to establish the scope of the application. This scope isdefined solely by the pending claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a switching arrangement of the inventive lubricantinjector;

FIG. 2 shows a schematic sectional view through a first exemplaryembodiment of the inventive lubricant injector;

FIG. 3 shows a schematic depiction of the inventive lubricant injectorin different switching states during a lubricant introduction cycle;

FIG. 4 shows a schematic sectional view through a second preferredexemplary embodiment of the inventive lubricant injector;

FIG. 5 shows a schematic sectional view through a third preferredexemplary embodiment of the inventive lubricant injector;

FIG. 6 shows a schematic sectional view through a fourth preferredexemplary embodiment of the inventive lubricant injector; and

FIG. 7 shows a schematic sectional view through a preferred exemplaryembodiment of an inventive lubricant injector block.

DETAILED DESCRIPTION

In the following, identical or functionally equivalent elements aredesignated by the same reference numbers.

FIG. 1 shows a schematic circuit diagram of a lubricant injector 1 thatis impinged with lubricant from a lubricant pump assembly, wherein thelubricant is provided, pressurized, via a lubricant line 4 on alubricant inlet 6 of the lubricant injector 1. The lubricant pumpassembly 2 here is configured such that lubricant is pressurized in thelubricant line 4 during a pumping cycle, and at the end of the pumpingcycle the lubricant line 4 is switched pressureless. “Pressureless” heremeans, for example, a pressure of less than 70 bar, while thepressurization falls in a significantly higher pressure range of, forexample, more than 100 bar.

Such lubricant pumps are known from the prior art and are therefore notfurther described.

As can further be seen from FIG. 1, the inventive lubricant injectorfurthermore includes a control unit 8 and a metering unit 10. Thecontrol unit 8 includes a metering piston 12 that is bringable from afirst (I) into a second (II) switching state. Here the control piston 12is preloaded in the first switching state I using a preload element 14,in particular a spring element.

The metering element 10 includes a piston 16 that includes a firstpiston workspace 18 configured as a first metering chamber, and a secondpiston workspace 20 configured as a second metering chamber. If alubricant pressure abuts on the lubricant inlet 6, then in the firstswitching state I lubricant is conducted via the control piston 12 intothe second metering chamber 20 by a first lubricant channel 22. Due tothe increasing volume of the lubricant in the metering chamber 20 thepiston 16 is displaced toward the first metering chamber 18 so thatlubricant is conducted from the first metering chamber 18 via a secondlubricant channel 24 to a lubricant outlet 26 and from there out to alubricant consumer 28.

If the piston 16 has reached its maximum stroke towards the firstmetering chamber 18, i.e., a further advancing toward the meteringchamber 18 is not possible, the pressure of the lubricant increases inthe second metering chamber 20, in the first lubricant channel 22, andalso at the lubricant inlet 6. Furthermore, a lubricant switchoverpressure channel 30 is disposed on the lubricant inlet 6, whichlubricant switchover pressure channel 30 conducts lubricant toward acontrol-piston workspace upon exceeding of a certain lubricant pressureat the lubricant inlet 6 or the control piston 12. The control piston 12is thereby transferred into the second switching state II against thepreload force of the preload element 14.

In the second switching state II lubricant is now supplied via thesecond lubricant channel of the first metering chamber 18, which in turneffects an advancing movement of the piston 16 toward the secondmetering chamber 20. The lubricant present in the second meteringchamber 20 is thereby pumped via the first lubricant channel 22 towardthe lubricant outlet 26.

If at the end of the lubricant pumping cycle the lubricant line 4 pumpsno further or little lubricant toward the lubricant inlet 6, thepressure drops in the lubricant line 4 and thus at the lubricant inlet6. If the lubricant pressure has fallen below a certain threshold valuethat is preferably determined via the preload force of the preloadelement 14, the control piston 12 can be returned via the preloadelement 14 into its first switching state I.

FIG. 2 schematically shows a first preferred exemplary embodiment of theinventive lubricant injector 1 at the end of the first switching stateI. As can be seen from FIG. 2, the lubricant injector 1 includes ahousing 34 wherein the control piston 12 and the metering piston 16 aredisposed. Here the control piston 12 and the metering piston 16 can alsoeach be disposed in their own housings that are connectable to eachother. Rearward of the control piston 12 the lubricant inlet isschematically indicated. In order to be able to provide the first andthe second switching state a first control space 36, in particular aring space, and a second control space 38 that is also preferablyconfigured as a ring space are disposed on the control piston 12. As canfurther be seen from FIG. 2, in the depicted first switching state I thelubricant inlet 6 is connected via the ring space 36 to the firstlubricant channel 22 and the second metering chamber 20 of the piston16. On the other hand the lubricant channel 24 is connected via the ringspace 38 to a lubricant outlet channel 40, via which lubricant isconducted toward the lubricant outlet 26 disposed on the spring element14. Since a further advancing of the piston 16 toward the first meteringchamber 18 is no longer possible in the state depicted in FIG. 2, thepressure of the lubricant increases in the second metering chamber 20,the first lubricant channel 22, and at the lubricant inlet 6. If thepressure at the lubricant inlet 6 or at the control piston 12 exceeds acertain value, then lubricant can be conducted via the switchoverpressure channel 30 not shown here toward the control-piston workspace32 so that the control piston 12 can be moved into its second switchingstate II against the preload of the preload element 14.

FIGS. 3a to 3f schematically show the movement of control piston andmetering piston during exemplarily shown switching states. Here FIG. 3ashows an initial state wherein the lubricant inlet 6 is connected viathe first ring space 36 to the first lubricant channel 22 and guideslubricant toward the second metering chamber 20 of the metering piston16. The piston 16 is thereby moved toward the first metering chamber 18wherein lubricant from the previous cycle is located, whereby thelubricant present in the chamber 18 is pumped via the lubricant channel24, the second control space 38 and the lubricant outlet channel 40toward lubricant outlet 26. FIG. 3b shows an inventive lubricantinjector in an intermediate state, while lubricant is pumped from thefirst metering chamber 18 toward lubricant outlet 26. FIG. 3c shows astate wherein the metering piston 16 has displaced the lubricant fromthe first metering chamber 18 and guided lubricant into the controlpiston workspace 32 of the control piston 12. Via the pressure built upin the control-piston space the control piston 12 is displaced towardthe lubricant outlet 26 against the preload of the preload element untilthe control piston 12 reaches its second switching state II. In thesecond switching state, as FIG. 3d shows, the second ring space 38 isconnected to the lubricant inlet 6 so that lubricant is conducted viathe second ring space 38 and the second lubricant channel 24 into thefirst metering chamber 18. This in turn effects an advancing of themetering piston toward the second metering chamber 20, whereby lubricantis pumped via the first lubricant channel 22 and the first ring space 36toward the lubricant outlet 26. For this purpose in particular alubricant outlet channel 42 is disposed. In the end state of the secondswitching state, which is shown in FIG. 3e , the metering piston 16 isin turn maximally displaced toward the first metering chamber 20 and thefirst metering chamber is completely filled with lubricant. Afterreaching this switching state the end of the lubricant pumping cycle isalso usually reached so that no further or only little lubricant ispumped from the lubricant pump toward lubricant inlet 6. The lubricantpressure thereby drops in the lubricant line 4 and also in thecontrol-piston workspace 32 so that with the aid of the preload element14 the control piston 12 can be pushed back into the initial state 12(see FIG. 3f ).

Furthermore, as can be seen in particular in FIG. 2 a plurality ofadjusting screws 44, 46, 48 are provided on the inventive lubricantinjector 1. Here the stroke of the control piston 12 can by finelyadjusted by the adjusting screw 44. Alternatively the adjusting screw 44can also be configured as a simple cover element. The adjusting screws46 and 48 advantageously represent so-called metering screws, via whichthe stroke of the metering piston 16 and thus the metering volume isadjustable. Accordingly via these adjusting screws 46, 48 a meteredquantity of the lubricant can be continuously adjustable externally.Alternatively it is of course also possible to determine the meteringvia the size of the metering piston 16. In order to monitor a functionof the lubricant injector 1, a sensor, in particular a proximity sensor,can additionally be provided on the end surface of the metering piston16 or of the control piston 12, which sensor determines whether thelubricant injector 1 functions as desired. Alternatively or additionallyan indicator pin can also be provided on the metering piston 16 and/orcontrol piston 12, which makes possible an optical functionalmonitoring.

As can be seen in particular in FIGS. 2 and 3, in comparison to theprior art the inventive lubricant injector 1 is assembled from very fewelements, so that the entire construction is simplified. Furthermore itis advantageous that lubricant is pumped to the lubricant outlet 26 bothdirectly from the first metering chamber 18 and the second meteringchamber 20 during a lubricant pumping cycle, which increases the pumpedquantity of lubricant overall.

This inventive design that lubricant is pumped directly to a lubricantoutlet 26 both from the first metering chamber 18 and from the secondmetering chamber 20 also makes possible further inventive designs thatare described, for example, in FIGS. 4 to 6. In contrast to theexemplary embodiments depicted in FIGS. 2 and 3, FIGS. 4 to 6 includenot only one lubricant outlet 26 but a second lubricant outlet 50. Here,as FIG. 4 shows, for example, the first lubricant-outlet channel 40 maynot, as depicted in FIG. 2, extend toward the first lubricant outlet 26,but can extend to a second lubricant outlet 50. As a result lubricantcan be provided from the first metering chamber 18 to the secondlubricant outlet 50, while the lubricant from the second lubricantchamber 20 is pumped via the second lubricant-outlet channel 42, asdiscussed in FIG. 2, toward the first lubricant outlet 26.

FIG. 4 schematically shows yet another preferred design of the lubricantinjector 1, since the lubricant outlet channel 40 not only opensdirectly into the lubricant outlet 50, but it is further provided thatthe lubricant outlet 50 need not obligatorily be used as lubricantoutlet. For this purpose a closure element can be fitted in thelubricant outlet 50, which closure element 52 sealingly closes thelubricant outlet 50. However, in order that the lubricant pumped fromthe first metering chamber 18 can be conducted out of thelubricant-outlet channel 40 toward a lubricant outlet, alubricant-outlet connecting channel 54 is furthermore provided that,with a closed second lubricant outlet 50, transports lubricant from thelubricant outlet channel 40 toward the first lubricant outlet 26. On theother hand if the second lubricant outlet 50 is to be used as alubricant outlet, a connecting element 56 can be used in the lubricantoutlet 50 that is preferably configured such that it blocks the accessto the lubricant-outlet connecting channel 54. In the exemplaryembodiment depicted this is achieved via a cone fitting 58, 60 whereinthe cone 58 of the connecting element 56 can be fitted directly into theconical opening 60 on the lubricant outlet 50 and blocks thelubricant-outlet connecting channel 54.

Instead of a connecting element designed in this manner another device,for example, a vent device, can be used in the lubricant outlet, whichdevice controls the opening or closing of lubricant outlet 26; 50 orlubricant-outlet connecting channel 54 such that the dispensing locationand/or the dispensed amount of lubricant can again be influenced in atargeted manner.

In order to correspondingly variably design the second lubricant outlet50, a connecting device 62, for example in the form of a thread, can beformed on the lubricant outlet 50, which connecting device 62 ensures aninterference-fit receiving, for example, of the closure element 52 or ofthe connecting element 56. Alternatively, however, such a connection canalso be achieved via a plug connection or snap connection.

FIG. 5 shows a further advantageous design of the inventive lubricantinjector 1, wherein not only the second lubricant outlet 50, but alsothe first lubricant outlet 26 are variably designed. For this purposethe first lubricant outlet 26 is no longer, as depicted in FIG. 2, madepossible via the spring space of the preload element 14, but is also,like the second lubricant outlet 50 itself, disposed in the housing 34of the lubricant injector 1. For this purpose the secondlubricant-outlet channel 44 is not only configured as a ring space aboutthe control piston but also includes an extension 64 that opens directlyinto the first lubricant outlet 26. If the lubricant outlet 26 is closedby the closure element 52, lubricant can also be conducted via thelubricant-outlet connecting channel 54 from the first lubricant outlet26 to the second lubricant outlet 50. In order to block thelubricant-outlet connecting channel 54, a fitting 58 can in turn, asalready described with reference to FIG. 4, be disposed on thelubricant-outlet connecting element 56, which fitting 58 interacts witha counter-fitting 60 and closes the lubricant-outlet connecting channel54.

FIG. 6 schematically shows a further preferred exemplary embodiment,wherein the second lubricant outlet 50 is disposed parallel to the firstlubricant outlet 26. Here the first lubricant outlet 26 is in turnformed via the return element 14. Furthermore it is depicted in FIG. 6that the connecting element 56 is fitted with interference fit in thesecond lubricant outlet 50. The connecting element 56 furthermoreincludes an inlet opening 66 that fluidly connects the lubricant-outletchannel 40 to the lubricant outlet 50. Simultaneously a lubricant-outletconnecting channel 54 is closed by the interference-fit receiving of theconnecting element 56 in the lubricant outlet 50 so that lubricant canescape from the first metering chamber 18 only via the second lubricantoutlet 50. On the other hand, as known, lubricant is supplied from thesecond metering chamber 20 to the first lubricant outlet 26.

The inventive lubricant injectors are advantageous in particular if aplurality of consumers are to be impinged with lubricant. Then with asingle lubricant injector not only one consumer but at least twoconsumers can be supplied with lubricant. This saves costs and reducesthe installation space required.

Furthermore it is depicted in FIG. 7 that the lubricant injectors cannot only be provided as individual elements but also disposable as ablock one-behind-the-other. Here the lubricant injectors can beconnected in series in a common housing, as individual elements, or evenas a plurality of blocks.

FIG. 7 here shows a schematic plan view from the control-piston side ofa lubricant injector block 100, which is constructed of a plurality, sixare depicted, of lubricant injectors 1-1, 1-2, 1-3, 1-4, 1-5, and 1-6,which are disposed in the common housing 34. Of course, however, thelubricant injectors or the control pistons or metering pistons can alsobe disposed in separate housings, that are connected in a mannercorresponding to a block. The lubricant injectors 1-1, 1-2, 1-3, 1-4,1-5, and 1-6 themselves can be configured as depicted in FIG. 6 and eachinclude a control piston 12-1, 12-2, 12-3, 12-4, 12-5, and 12-6, as wellas a metering piston (not depicted) disposed thereunder in the view ofFIG. 7. Furthermore FIG. 7 shows that a central lubricant inlet 68 isdisposed on the housing 34, via which each of the lubricant injectors1-1 to 1-6 is impingeable with lubricant. For this purpose in particulara central channel 72 is provided in the housing 34, which centralchannel 72 connects the lubricant inlets of the control pistons 12-1 to12-6 to each other and connects them in series. Furthermore a centrallubricant outlet 70 can be provided on the housing, via which lubricantwould be guidable from the central channel 72 into a further lubricantinjector block 100. If no further lubricant injector block 100 is to beprovided with lubricant, then the central lubricant outlet 70 is closedso that the lubricant supplied to all lubricant injectors 1 connected inseries, or lubricant injector blocks 100, can only escape via therespective lubricant outlets 26, 50 of the individual lubricantinjectors 1.

Such an arrangement is particularly advantageous since with one elementnot only one consumer but a plurality of consumers can be supplied withlubricant. Installation space can in turn thereby be saved.

In particular with the inventive lubricant injector a lubricant injectorcan be provided that is easy to manufacture due to the small number ofparts. Simultaneously the preload springs need not, as in the prior art,be matched to each other, since only one preload spring is required perlubricant injector. With the aid of the closure screws influence canalso be exerted on the metered amount.

REFERENCE NUMBER LIST

-   -   1 Lubricant injector    -   100 Lubricant injector block    -   2 Lubricant pump assembly    -   4 Lubricant line    -   6 Lubricant inlet    -   8 Control unit    -   10 Metering unit    -   12 Control piston    -   14 Preload element    -   16 Metering piston    -   18 First metering chamber    -   20 Second metering chamber    -   22 First lubricant channel    -   24 Second lubricant channel    -   26 Lubricant outlet    -   28 Lubricant consumer    -   30 Lubricant switchover pressure channel    -   32 Control-piston workspace    -   34 Housing    -   36 First control space    -   38 Second control space    -   40 First lubricant outlet channel    -   42 Second lubricant outlet channel    -   44, 46, 48 Adjusting screws    -   50 Second lubricant outlet    -   52 Closure element    -   54 Lubricant-outlet connecting channel    -   56 Connecting element    -   58 Conical fitting    -   60 Conical counter-fitting    -   62 Thread    -   64 Extension of the second lubricant outlet channel    -   66 Opening in the connecting element    -   68 Central lubricant inlet in the lubricant injector block    -   70 Central lubricant outlet from the lubricant injector block    -   72 Lubricant central channel    -   I First switching state    -   II Second switching state

The invention claimed is:
 1. A lubricant injector comprising at leastone lubricant inlet, at least one lubricant outlet, a control piston anda metering piston, wherein the control piston is configured to conductlubricant from the lubricant inlet to the metering piston and themetering piston is configured to pump the lubricant provided by thecontrol piston to the at least one lubricant outlet, wherein themetering piston includes a first metering chamber and a second meteringchamber that are each connected to the at least one lubricant outlet sothat both from the first metering chamber and from the second meteringchamber lubricant is conductible to the at least one lubricant outlet,and wherein the lubricant injector further includes a first lubricantchannel and a second lubricant channel, wherein the first lubricantchannel is configured to connect the second metering chamber to thelubricant inlet or to the at least one lubricant outlet, and the secondlubricant channel is configured to connect the first metering chamber tothe lubricant inlet or to the at least one lubricant outlet wherein thecontrol piston includes a first control space and a second controlspace, wherein in a first switching state of the control piston thelubricant inlet is connected via the first control space, but not viathe second control space, to the first lubricant channel and the secondmetering chamber, and in a second switching state the lubricant inlet isconnected via the second control space, but not via the first controlspace, to the second lubricant channel and the first metering chamber,wherein the first lubricant channel is connected to the at least onelubricant outlet via a first lubricant-outlet channel, and the secondlubricant channel is connected to the at least one lubricant outlet viaa second lubricant-outlet channel, and wherein the at least onelubricant outlet comprises a first lubricant outlet and a secondlubricant outlet.
 2. The lubricant injector according to claim 1,wherein in the first switching state of the control piston the firstmetering chamber of the metering piston is connected to the at least onelubricant outlet via the second lubricant channel and the second controlspace and in the second switching state the second metering chamber ofthe metering piston is connected to the at least one lubricant outletvia the first lubricant channel and the first control space.
 3. Thelubricant injector according to claim 1, wherein the first lubricantoutlet is connected to the first lubricant-outlet channel and the secondlubricant outlet is connected to the second lubricant-outlet channel. 4.The lubricant injector according to claim 1, wherein the first lubricantoutlet is connectable via the first lubricant-outlet channel the firstcontrol space, and the first lubricant channel to the second meteringchamber, and the second lubricant outlet is connectable via the secondlubricant-outlet channel, the second control space, and the secondlubricant channel to the first metering chamber.
 5. The lubricantinjector according to claim 1, wherein at least one further lubricantoutlet is provided at the first and/or second lubricant-outlet channel.6. The lubricant injector according to claim 1, wherein a screw thread,a snap connection, and/or a plug connection, is provided on the at leastone lubricant outlet with which the at least one lubricant outlet isconnectable to a valve assembly, a closure element or a connectingelement for connecting a lubricant line.
 7. The lubricant injectoraccording to claim 6, wherein at least one lubricant outlet comprises aspring space for the control-piston preload element.
 8. The lubricantinjector according to claim 1, further including a return springconfigured to bias the control piston toward the first switching state.9. The lubricant injector according to claim 1, wherein the controlpiston includes a control-piston workspace that is impingeable withlubricant in order to shift the control piston into the second switchingstate against a preload of a preload element.
 10. The lubricant injectoraccording to claim 9, wherein the control-piston workspace is connectedto a lubricant switchover pressure channel, which is configured toconduct lubricant into the control-piston workspace if a certainlubricant pressure abuts on the lubricant inlet and/or in the firstcontrol space of the control piston.
 11. The lubricant injectoraccording to claim 10, wherein the lubricant switchover pressure channelis connected to the lubricant inlet and/or the first control space ofthe control piston.
 12. The lubricant injector according to claim 1,wherein at least the first and the second lubricant outlet are disposedon different sides of the lubricant injector, or at least the first andthe second lubricant outlet are disposed on the same side of thelubricant injector.
 13. The lubricant injector according to claim 1,wherein at least one metering chamber is connectable using an adjustingscrew via which a stroke of the metering piston and/or of the controlpiston is adjustable.
 14. A lubricant injector block with at least twolubricant injectors according to claim 1 connected in series.
 15. Thelubricant injector block according to claim 14, including a lubricantcentral channel on the lubricant injector block via which the at leasttwo lubricant inlets of the at least two lubricant injectors aresupplyable with lubricant.
 16. The lubricant injector block according toclaim 15, including a central lubricant inlet and a central lubricantoutlet on the lubricant injector block that are connected to each othervia the lubricant central channel, wherein the central lubricant outletis closable with a closure element or connectable to a further lubricantinjector or a further lubricant injector block.
 17. A lubricant injectorcomprising at least one lubricant inlet, at least one lubricant outlet,a control piston and a metering piston, wherein the control piston isconfigured to conduct lubricant from the lubricant inlet to the meteringpiston and the metering piston is configured to pump the lubricantprovided by the control piston to the at least one lubricant outlet,wherein the metering piston includes a first metering chamber and asecond metering chamber that are each connected to the at least onelubricant outlet so that both from the first metering chamber and fromthe second metering chamber lubricant is conductible to the at least onelubricant outlet, and wherein the lubricant injector further includes afirst lubricant channel and a second lubricant channel, wherein thefirst lubricant channel is configured to connect the second meteringchamber to the lubricant inlet or to the at least one lubricant outlet,and the second lubricant channel is configured to connect the firstmetering chamber to the lubricant inlet or to the at least one lubricantoutlet wherein the control piston includes a first control space and asecond control space, wherein in a first switching state of the controlpiston the lubricant inlet is connected via the first control space tothe first lubricant channel and the second metering chamber, and in asecond switching state the lubricant inlet is connected via the secondcontrol space to the second lubricant channel and the first meteringchamber, wherein the first lubricant channel is connected to the atleast one lubricant outlet via a first lubricant-outlet channel, and thesecond lubricant channel is connected to the at least one lubricantoutlet via a second lubricant-outlet channel, wherein the at least onelubricant outlet comprises a first lubricant outlet and a secondlubricant outlet, and wherein the first control space is a first annularspace in a side wall of the control piston and the second control spaceis a second annular space in the side wall of the control piston, thesecond annular space being separate from the first annular space.
 18. Alubricant injector comprising at least one lubricant inlet, at least onelubricant outlet, a control piston and a metering piston, wherein thecontrol piston is configured to conduct lubricant from the lubricantinlet to the metering piston and the metering piston is configured topump the lubricant provided by the control piston to the at least onelubricant outlet, wherein the metering piston includes a first meteringchamber and a second metering chamber that are each connected to the atleast one lubricant outlet so that both from the first metering chamberand from the second metering chamber lubricant is conductible to the atleast one lubricant outlet, and wherein: the lubricant injector furtherincludes a first lubricant channel and a second lubricant channel,wherein the first lubricant channel is configured to connect the secondmetering chamber to the lubricant inlet or to the lubricant outlet, andthe second lubricant channel is configured to connect the first meteringchamber to the lubricant inlet or to the lubricant outlet wherein thecontrol piston includes a first control space and a second controlspace, wherein in a first switching state of the control piston thelubricant inlet is connected via the first control space to the firstlubricant channel and the second metering chamber, and in a secondswitching state the lubricant inlet is connected via the second controlspace to the second lubricant channel and the first metering chamber,the first lubricant channel is connected to the at least one lubricantoutlet via a first lubricant-outlet channel, and the second lubricantchannel is connected to the at least one lubricant outlet via a secondlubricant-outlet channel, and the at least one lubricant outletcomprises a first lubricant outlet and a second lubricant outlet, andfurther including at least one lubricant-outlet connecting channel thatconnects at least the first lubricant outlet and second lubricantoutlet.
 19. The lubricant injector according to claim 18, wherein atleast one of the at least one lubricant outlet is closable, andlubricant is guidable via at least one lubricant-outlet connectingchannel to an open one of the at least one open lubricant outlet. 20.The lubricant injector according to claim 18, wherein a valve assembly,a closure element, or a connecting element is disposed in at least onelubricant outlet, and configured to open the corresponding lubricantoutlet or the lubricant-outlet connecting channel.